Harlan's Hawk (Buteo jamaicensis harlani): A Valid Subspecies

Abstract

Abstract During surveys of 19 different rivers in central and southwestern Alaska, north of the Alaska Peninsula, all Red-tailed Hawks (Buteo jamaicensis) seen were either B. j. harlani or harlani intergrades, demonstrating that harlani does have a breeding range exclusive of other Red-tailed Hawk subspecies and is, therefore, a legitimate subspecies. The range of harlani intergrades was widespread and overlapped the harlani breeding range entirely. The findings presented suggest that the breeding range for harlani and its intergrade forms, exclusive of other Red-tailed Hawk subspecies, is: west to Norton Sound, east to the Alaska Range west slope, north to the tree line, and south to the Alaska Peninsula. Harlani may have diverged morphologically from other Red-tailed Hawks by isolation in a Pleistocene epoch glacial refugium, as has been suggested for other northern bird groups. The possibility of paripatric speciation, however, must also be considered. The characteristics of red in the tail (even small amounts) and white body plumage are discussed as likely intergrade traits.